1. Field of the Invention
The present invention is related to metal organic compounds. More particularly, the invention is related to tellurium containing organic compounds and a method for their synthesis.
2. Description of the Prior Art
Metal Organic Chemical Vapor Deposition film growth of Mercury-Cadmium-Telluride (HgCdTe) is adversely affected by the high growth temperatures of 400.degree. C. to 425.degree. C. which are needed to crack diethyl telluride. Problems include mercury evaporation from the film and diffusion across the interface between the film and the substrate. Ditertiarybutyl telluride has been used to deposit CdTe and HgTe films at 250.degree. C. with excellent results. This material has been shown to work at temperatures as low as 220.degree. C. to 230.degree. C. However, the resulting metal films are inadequate for applications in sensitive IR detectors. Furthermore, the preparation of the tellurium source compound, ditertiarybutyl telluride, is a low yield process.
Existing processes for preparing dialkyl tellurides such as diethyl telluride use alkali metal tellurides as reactants. Current methods of preparing alkali metal tellurides employ sodium triethylborohydride or sodium borohydride. These boron containing compounds are expensive and leave trace amounts of boron in the alkali metal tellurides produced. As a result, alkali metal tellurides are expensive and contain impurities rendering them unsuitable for use in preparing electronic grade dialkyl tellurides.
Alkali metal tellurides are also prepared by reaction of an alkali metal with tellurium in liquid ammonia. The preparation requires cryogenic conditions and is hazardous because liquid ammonia is used.